Sound intensity level or acoustic intensity level is a logarithmic measure of the sound intensity (measured in W/m2), in comparison to a reference level.
The measure of a ratio of two sound intensities is
where I1 and I0 are the intensities.
The sound intensity level is given the letter "LI" and is measured in "dB". The decibel is a dimensionless quantity.
If I0 is the standard reference sound intensity
(W = watt), then instead of "dB SPL" we use "dB SIL". (SIL = sound intensity level).
Read more about this topic: Sound Intensity
Famous quotes containing the words sound, intensity and/or level:
“Today we seek a moral basis for peace.... It cannot be a lasting peace if the fruit of it is oppression, or starvation, cruelty, or human life dominated by armed camps. It cannot be a sound peace if small nations must live in fear of powerful neighbors. It cannot be a moral peace if freedom from invasion is sold for tribute.”
—Franklin D. Roosevelt (1882–1945)
“As siblings we were inextricably bound, even though our connections were loose and frayed.... And each time we met, we discovered to our surprise and dismay how quickly the intensity of childhood feelings reappeared.... No matter how old we got or how often we tried to show another face, reality was filtered through yesterday’s memories.”
—Jane Mersky Leder (20th century)
“It is only for a little while, only occasionally, methinks, that we want a garden. Surely a good man need not be at the labor to level a hill for the sake of a prospect, or raise fruits and flowers, and construct floating islands, for the sake of a paradise. He enjoys better prospects than lie behind any hill. Where an angel travels it will be paradise all the way, but where Satan travels it will be burning marl and cinders.”
—Henry David Thoreau (1817–1862)